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Active Oberon
Active Oberon is a general purpose programming language developed during 1996-1998 by the group around Niklaus Wirth and Jürg Gutknecht at the Swiss Federal Institute of Technology in Zürich (ETH Zurich). It is an extension of the programming language Oberon. The extensions aim at implementing active objects as expressions for parallelism. Compared to its predecessors, Oberon and Oberon-2, Active Oberon adds objects (with object-centered access protection and local activity control), system-guarded assertions, preemptive priority scheduling and a changed syntax for methods (named '' type-bound procedures'' in Oberon vocabulary). Objects may be ''active'', which means that they may be threads or processes. The operating system named ''Active Object System'' (AOS) in 2002, then due to trademark issues, renamed ''Bluebottle'' in 2005, and then renamed '' A2'' in 2008, especially the kernel, synchronizes and coordinates different active objects. Unlike Java or C#, objects may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Imperative Programming
In computer science, imperative programming is a programming paradigm of software that uses statements that change a program's state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program consists of commands for the computer to perform. Imperative programming focuses on describing ''how'' a program operates step by step, rather than on high-level descriptions of its expected results. The term is often used in contrast to declarative programming, which focuses on ''what'' the program should accomplish without specifying all the details of ''how'' the program should achieve the result. Imperative and procedural programming Procedural programming is a type of imperative programming in which the program is built from one or more procedures (also termed subroutines or functions). The terms are often used as synonyms, but the use of procedures has a dramatic effect on how imperative programs appear and how they are constructed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oberon-2
Oberon-2 is an extension of the original Oberon programming language that adds limited reflection and object-oriented programming facilities, open arrays as pointer base types, read-only field export, and reintroduces the FOR loop from Modula-2. It was developed in 1991 at ETH Zurich by Niklaus Wirth and Hanspeter Mössenböck, who is now at Institut für Systemsoftware (SSW) of the University of Linz, Austria. Oberon-2 is a superset of Oberon, is fully compatible with it, and was a redesign of Object Oberon. Oberon-2 inherited limited reflection and single inheritance ("type extension") without the interfaces or mixins from Oberon, but added efficient virtual methods ("type bound procedures"). Method calls were resolved at runtime using C++-style virtual method tables. Compared to fully object-oriented languages like Smalltalk, in Oberon-2, basic data types and classes are not objects, many operations are not methods, there is no message passing (it can be emulated somewhat b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zonnon
Zonnon is a general purpose programming language in the line or family of the preceding languages Pascal, Modula, and Oberon. Jürg Gutknecht is the author. Its conceptual model is based on objects, definitions, implementations, and modules. Its computing model is concurrent, based on active objects which interact via syntax controlled dialogs. The language is being developed at ETH Zürich Institute for Computer Systems by Professor Jürg Gutknecht. Zonnon introduces the concept of 'active objects' which are used to represent real world concurrent objects within computer programs. The Zonnon Language Report was written by Brian Kirk (director at Robinsons Associates), and David Lightfoot (Oxford Brookes University) working with Gutknecht (ETH, Zürich) and Dr. Eugene Zueff (Евгений Зуев) (Moscow State University). The first book about Zonnon was published by the N. I. Lobachevsky State University of Nizhny Novgorod (a.k.a., Nizhni Novgorod State University). [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fork (software Development)
In software engineering, a project fork happens when developers take a copy of source code from one software package and start independent development on it, creating a distinct and separate piece of software. The term often implies not merely a development branch, but also a split in the developer community; as such, it is a form of schism. Grounds for forking are varying user preferences and stagnated or discontinued development of the original software. Free and open-source software is that which, by definition, may be forked from the original development team without prior permission, and without violating copyright law. However, licensed forks of proprietary software (''e.g.'' Unix) also happen. Etymology The word "fork" has been used to mean "to divide in branches, go separate ways" as early as the 14th century. In the software environment, the word evokes the fork system call, which causes a running process to split itself into two (almost) identical copies that (ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exception Handling
In computing and computer programming, exception handling is the process of responding to the occurrence of ''exceptions'' – anomalous or exceptional conditions requiring special processing – during the execution of a program. In general, an exception breaks the normal flow of execution and executes a pre-registered ''exception handler''; the details of how this is done depend on whether it is a hardware or software exception and how the software exception is implemented. Exception handling, if provided, is facilitated by specialized programming language constructs, hardware mechanisms like interrupts, or operating system (OS) inter-process communication (IPC) facilities like signals. Some exceptions, especially hardware ones, may be handled so gracefully that execution can resume where it was interrupted. Definition The definition of an exception is based on the observation that each procedure has a precondition, a set of circumstances for which it will terminate "normal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal (computing)
Signals are standardized messages sent to a running program to trigger specific behavior, such as quitting or error handling. They are a limited form of inter-process communication (IPC), typically used in Unix, Unix-like, and other POSIX-compliant operating systems. A signal is an asynchronous notification sent to a process or to a specific thread within the same process to notify it of an event. Common uses of signals are to interrupt, suspend, terminate or kill a process. Signals originated in 1970s Bell Labs Unix and were later specified in the POSIX standard. When a signal is sent, the operating system interrupts the target process' normal flow of execution to deliver the signal. Execution can be interrupted during any non-atomic instruction. If the process has previously registered a signal handler, that routine is executed. Otherwise, the default signal handler is executed. Embedded programs may find signals useful for inter-process communications, as signals are n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Sharp (programming Language)
C# (pronounced ) is a general-purpose, high-level multi-paradigm programming language. C# encompasses static typing, strong typing, lexically scoped, imperative, declarative, functional, generic, object-oriented (class-based), and component-oriented programming disciplines. The C# programming language was designed by Anders Hejlsberg from Microsoft in 2000 and was later approved as an international standard by Ecma (ECMA-334) in 2002 and ISO/IEC (ISO/IEC 23270) in 2003. Microsoft introduced C# along with .NET Framework and Visual Studio, both of which were closed-source. At the time, Microsoft had no open-source products. Four years later, in 2004, a free and open-source project called Mono began, providing a cross-platform compiler and runtime environment for the C# programming language. A decade later, Microsoft released Visual Studio Code (code editor), Roslyn (compiler), and the unified .NET platform (software framework), all of which support C# and are free, open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Java (programming Language)
Java is a high-level, class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let programmers ''write once, run anywhere'' ( WORA), meaning that compiled Java code can run on all platforms that support Java without the need to recompile. Java applications are typically compiled to bytecode that can run on any Java virtual machine (JVM) regardless of the underlying computer architecture. The syntax of Java is similar to C and C++, but has fewer low-level facilities than either of them. The Java runtime provides dynamic capabilities (such as reflection and runtime code modification) that are typically not available in traditional compiled languages. , Java was one of the most popular programming languages in use according to GitHub, particularly for client–server web applications, with a reported 9 million developers. Java was originally developed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A2 (operating System)
A2 (formerly named Active Object System (AOS), and then Bluebottle) is a modular, object-oriented operating system, with some unconventional features, including automatic garbage-collected memory management, and a zooming user interface. It was developed originally at ETH Zurich in 2002. It is free and open-source software under a BSD-like license. History A2 is the next generation of Native Oberon, the x86 PC version of Niklaus Wirth's operating system Oberon. Out of printElectronic reprint./ref> It is small, fast, supports multiprocessing computers, and provides soft real-time computing operation. It is entirely written in an upward-compatible dialect of the programming language Oberon named Active Oberon. Both languages are members of the Pascal family, along with Modula-2. A2's design allows developing efficient systems based on ''active objects'' which run directly on hardware, with no mediating interpreter or virtual machine. Active objects represent a combinati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process (computer Science)
In computing, a process is the instance of a computer program that is being executed by one or many threads. There are many different process models, some of which are light weight, but almost all processes (even entire virtual machines) are rooted in an operating system (OS) process which comprises the program code, assigned system resources, physical and logical access permissions, and data structures to initiate, control and coordinate execution activity. Depending on the OS, a process may be made up of multiple threads of execution that execute instructions concurrently. While a computer program is a passive collection of instructions typically stored in a file on disk, a process is the execution of those instructions after being loaded from the disk into memory. Several processes may be associated with the same program; for example, opening up several instances of the same program often results in more than one process being executed. Multitasking is a method to allow mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread (computer Science)
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems. In Modern Operating Systems, Tanenbaum shows that many distinct models of process organization are possible.TANENBAUM, Andrew S. Modern Operating Systems. 1992. Prentice-Hall International Editions, ISBN 0-13-595752-4. In many cases, a thread is a component of a process. The multiple threads of a given process may be executed concurrently (via multithreading capabilities), sharing resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its executable code and the values of its dynamically allocated variables and non- thread-local global variables at any given time. History Threads made an early appearance under the name of "tasks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Method (computer Programming)
A method in object-oriented programming (OOP) is a procedure associated with a message and an object. An object consists of ''state data'' and ''behavior''; these compose an ''interface'', which specifies how the object may be utilized by any of its various consumers. A method is a behavior of an object parametrized by a consumer. Data is represented as properties of the object, and behaviors are represented as methods. For example, a Window object could have methods such as open and close, while its state (whether it is open or closed at any given point in time) would be a property. In class-based programming, methods are defined within a class, and objects are instances of a given class. One of the most important capabilities that a method provides is ''method overriding'' - the same name (e.g., area) can be used for multiple different kinds of classes. This allows the sending objects to invoke behaviors and to delegate the implementation of those behaviors to the receiving o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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